SMS: Android's "date" is Sailfish's "endTime", not "startTime"

[mcg-android]

The column "date" in Android's mmssms.db appears to represent the time an outgoing SMS message was sent and the time an incoming SMS message was received.

Sailfish apparently stores the time an outgoing SMS message was sent and the time an incoming SMS message was received in the "endTime" field of commhistory.db.

The app "SMS Backup & Restore" uses the value of the "date" attribute of an "sms" element to fill the column "date" in Android's mmssms.db.

So I think the value of the "date" attribute of an "sms" element created by converter.py should not be set to the "startTime" value from Sailfish's commhistory.db but to the "endTime" value.

Examples: Two SMS messages, one sent from an Android phone to a Sailfish phone, the other one sent in the other direction:

Android -> Jolla:
date      1599071411397
startTime 1599071414
endTime   1599071415
date_sent 1599071416951

Jolla -> Android:
endTime   1599071454
date_sent 1599071455000
date      1599071456069
startTime 1599071457